High temperatures in the south and heavy rains in the north. Why is the weather in my country so extreme this year?

Every summer, the main factor affecting our country’s weather is the subtropical high in the western Pacific.

In summer, the direct sunlight point will move northward, and the Western Pacific Subtropical High will also move northward. At the northwest edge of the Western Pacific Subtropical High, my country's rain belt will be formed. This This is because the warm and moist air flow from the ocean will move along the high pressure ridge, and when it meets the cold air, frontal rain will form. As the Western Pacific Subtropical High moves, my country's rain belts will also move accordingly, resulting in rainfall in South China, plum rain, and rainy season in North China.

In places governed by the Western Pacific Subtropical High, there will be sunny and cloudy weather and higher local temperatures. Recently, high temperature weather has occurred in many places in southern my country, mainly due to the strengthening of the subtropical high pressure, which has caused many places in the south to be dominated by the subtropical high pressure, resulting in the formation of high temperature weather.

Causes of heavy rains in the north:

First of all, the southwest vortex is formed under the special terrain and certain circulation conditions of the Qinghai-Tibet Plateau, and generally appears in Kowloon, Batang, Deqin, and Kangding , Qamdo area, and may also be formed in the Sichuan Basin. Most southwest vortices will dissipate within 36 hours, and a small number of southwest vortices can last for 6-7 days.

Not only that, 20% of the southwest vortex can move, of which 70.7% moves eastward and enters the ocean along the Yangtze River Basin. Only 21.12% moves northeastward and passes through multiple provinces. , including North China, and 9.1% will move southeast.

The southwest vortex is a rainfall system. Due to the low air pressure, the surrounding warm and humid air will be involved in it. The hot air rises, the temperature drops and condenses into water droplets, causing rainfall. So, it's been raining wherever the southwest vortex passes over the past few days.

A cold vortex is a cold vortex system that rotates at high altitude. Its central temperature is lower than the surrounding temperature and can also cause rainfall. It generally refers to a cold air mass at an altitude of 500 hPa (about 5,000 meters). . The southwest vortex is generally at a height of 700 hPa or 850 hPa, and the two heights are slightly different.

The low-altitude jet stream is a highly concentrated area of ​​momentum, heat and water vapor, generally at a height below 500 hPa. The southwest low vortex, cold vortex and low-level jet stream could each produce a heavy rain, but this time they interacted together, and this time under the influence of the southerly warm and moist airflow outside the subtropical high, they achieved continuous water vapor transport, so Caused widespread heavy rains.